Hey kellyx4, it probably is the electric hot water heater. My electric hot water heater is separate from the gas hot water heater. Neither one are on the monitor panel, but the water pump switch is on the monitor panel. All the manufacturers do things different, so unless someone has the same make and model as yours, it's a hit and miss on the advice.

I agree with DL, it pobably the electric hot water switch. Hook up your water hose fill the HWT and switch the switch on and wait and see ityour hot water is hot, if so you now what it is. Mine in my MH is like that and clsoe to the gas switch. good luck ps welcome to the forum.

Just wanted to follow up on the switch and answer my own question since it may help someone else. It is indeed the electric hot water heater. I tested it this weekend and it worked well. Thanks to all for the input.

Kelly,
While I'm a bit late to be much help, just for future reference, the switch you were asking about would be very unusual to be used for 12V-dc power. It is a typical 120V switch and those don't work well for the low voltages. The one marked as your water heater is a typical 12V switch. In general, the appearance of the switch is a good hint about what power it supplies.